dielectric barrier discharge (dbd) & progress in large...
TRANSCRIPT
Dielectric Barrier Discharge (DBD) amp Dielectric Barrier Discharge (DBD) amp Progress in LargeProgress in Large--Scale Ozone GenerationScale Ozone Generation
dd l l il l i
Progress in LargeProgress in Large Scale Ozone GenerationScale Ozone Generation
33rdrd Complex Plasma Summer InstituteComplex Plasma Summer Institute
Jose L Lopez PhDJose L Lopez PhDJose L Lopez PhDJose L Lopez PhD
Seton Hall UniversitySeton Hall UniversitySeto a U e s tySeto a U e s tyDepartment of PhysicsDepartment of Physics
South Orange New Jersey (USA)South Orange New Jersey (USA)
New Jersey New Jersey ndashndash Home of Seton HallHome of Seton Hall
New Jersey ndash The birth place of Plasma Science
Irving Langmuir (1881 ndash 1957) Nobel Laureate 1932Nobel Laureate 1932Birth of Plasma Science
BirthplaceBirthplace HobokenHoboken NewNew JerseyJersey
Irving Langmuir was one of the first scientists to work on plasmas and the first to refer to this 4th state of
tt l b th imatter as plasmas because their similarity to blood plasma
Irving Langmuir
Plasma Lighting Technology
Thomas EdisonIncandescent Light Bulb
Fluorescent Lamps Compact fluorescent blub
Daniel McFarlan Moore
BirthplaceBirthplace ofof thethe FluorescentFluorescent LightLight BulbBulb EdisonEdison (Menlo(Menlo Park)Park) WestWest OrangeOrange NJNJ
Plasma Enhanced Technology
A small section of amemory chip
Straight holes like these canbe etched with plasmasmemory chip be etched with plasmas
BirthplaceBirthplace ofof solidsolid--statestate microelectronicsmicroelectronicsBellBell LaboratoriesLaboratories MurrayMurray HillHill NJNJ
Microchip fabrication with plasmas
The US Department of Energyrsquos Princeton Plasma Physics Laboratory (PPPL) is acollaborative national center for plasma and fusion science Its primary mission is tocollaborative national center for plasma and fusion science Its primary mission is todevelop the scientific understanding and the key innovations which will lead to anattractive fusion energy source Associated missions include conducting world-classresearch along the broad frontier of plasma science and technology and providing thehighest quality of scientific education
National Spherical Torus Experiment (NSTX)
Atmospheric Cold PlasmasErich Kunhardt amp Kurt Becker
An Atmospheric Pressure Plasma Generated with a
(Courtesy of K Becker)
Capillary-Plasma-Electrode Discharge
Two Types of plasmas
bull High‐temperature plasmas (Hot Plasmas)g p p ( )Tiasymp Te ge107 Keg fusion plasmas
T asymp T asymp T le 2 x 104 KTi asymp Te asymp Tg le 2 x 104 Keg arc plasma at normal pressure
bull Low‐temperature plasmas (Cold Plasmas)Ti asymp Tg asymp 300 KT ltlt T le 105 KTi ltlt Te le 105 Keg low‐pressure glow discharge
high‐pressure cold plasma
Hot vs Cold PlasmasHot vs Cold Plasmas
LowLow--Temperature (ldquoColdrdquo) PlasmasTemperature (ldquoColdrdquo) Plasmas[Non[Non--equilibrium Nonequilibrium Non--Thermal]Thermal][Non[Non equilibrium Nonequilibrium Non Thermal]Thermal]
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
New Jersey New Jersey ndashndash Home of Seton HallHome of Seton Hall
New Jersey ndash The birth place of Plasma Science
Irving Langmuir (1881 ndash 1957) Nobel Laureate 1932Nobel Laureate 1932Birth of Plasma Science
BirthplaceBirthplace HobokenHoboken NewNew JerseyJersey
Irving Langmuir was one of the first scientists to work on plasmas and the first to refer to this 4th state of
tt l b th imatter as plasmas because their similarity to blood plasma
Irving Langmuir
Plasma Lighting Technology
Thomas EdisonIncandescent Light Bulb
Fluorescent Lamps Compact fluorescent blub
Daniel McFarlan Moore
BirthplaceBirthplace ofof thethe FluorescentFluorescent LightLight BulbBulb EdisonEdison (Menlo(Menlo Park)Park) WestWest OrangeOrange NJNJ
Plasma Enhanced Technology
A small section of amemory chip
Straight holes like these canbe etched with plasmasmemory chip be etched with plasmas
BirthplaceBirthplace ofof solidsolid--statestate microelectronicsmicroelectronicsBellBell LaboratoriesLaboratories MurrayMurray HillHill NJNJ
Microchip fabrication with plasmas
The US Department of Energyrsquos Princeton Plasma Physics Laboratory (PPPL) is acollaborative national center for plasma and fusion science Its primary mission is tocollaborative national center for plasma and fusion science Its primary mission is todevelop the scientific understanding and the key innovations which will lead to anattractive fusion energy source Associated missions include conducting world-classresearch along the broad frontier of plasma science and technology and providing thehighest quality of scientific education
National Spherical Torus Experiment (NSTX)
Atmospheric Cold PlasmasErich Kunhardt amp Kurt Becker
An Atmospheric Pressure Plasma Generated with a
(Courtesy of K Becker)
Capillary-Plasma-Electrode Discharge
Two Types of plasmas
bull High‐temperature plasmas (Hot Plasmas)g p p ( )Tiasymp Te ge107 Keg fusion plasmas
T asymp T asymp T le 2 x 104 KTi asymp Te asymp Tg le 2 x 104 Keg arc plasma at normal pressure
bull Low‐temperature plasmas (Cold Plasmas)Ti asymp Tg asymp 300 KT ltlt T le 105 KTi ltlt Te le 105 Keg low‐pressure glow discharge
high‐pressure cold plasma
Hot vs Cold PlasmasHot vs Cold Plasmas
LowLow--Temperature (ldquoColdrdquo) PlasmasTemperature (ldquoColdrdquo) Plasmas[Non[Non--equilibrium Nonequilibrium Non--Thermal]Thermal][Non[Non equilibrium Nonequilibrium Non Thermal]Thermal]
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
New Jersey ndash The birth place of Plasma Science
Irving Langmuir (1881 ndash 1957) Nobel Laureate 1932Nobel Laureate 1932Birth of Plasma Science
BirthplaceBirthplace HobokenHoboken NewNew JerseyJersey
Irving Langmuir was one of the first scientists to work on plasmas and the first to refer to this 4th state of
tt l b th imatter as plasmas because their similarity to blood plasma
Irving Langmuir
Plasma Lighting Technology
Thomas EdisonIncandescent Light Bulb
Fluorescent Lamps Compact fluorescent blub
Daniel McFarlan Moore
BirthplaceBirthplace ofof thethe FluorescentFluorescent LightLight BulbBulb EdisonEdison (Menlo(Menlo Park)Park) WestWest OrangeOrange NJNJ
Plasma Enhanced Technology
A small section of amemory chip
Straight holes like these canbe etched with plasmasmemory chip be etched with plasmas
BirthplaceBirthplace ofof solidsolid--statestate microelectronicsmicroelectronicsBellBell LaboratoriesLaboratories MurrayMurray HillHill NJNJ
Microchip fabrication with plasmas
The US Department of Energyrsquos Princeton Plasma Physics Laboratory (PPPL) is acollaborative national center for plasma and fusion science Its primary mission is tocollaborative national center for plasma and fusion science Its primary mission is todevelop the scientific understanding and the key innovations which will lead to anattractive fusion energy source Associated missions include conducting world-classresearch along the broad frontier of plasma science and technology and providing thehighest quality of scientific education
National Spherical Torus Experiment (NSTX)
Atmospheric Cold PlasmasErich Kunhardt amp Kurt Becker
An Atmospheric Pressure Plasma Generated with a
(Courtesy of K Becker)
Capillary-Plasma-Electrode Discharge
Two Types of plasmas
bull High‐temperature plasmas (Hot Plasmas)g p p ( )Tiasymp Te ge107 Keg fusion plasmas
T asymp T asymp T le 2 x 104 KTi asymp Te asymp Tg le 2 x 104 Keg arc plasma at normal pressure
bull Low‐temperature plasmas (Cold Plasmas)Ti asymp Tg asymp 300 KT ltlt T le 105 KTi ltlt Te le 105 Keg low‐pressure glow discharge
high‐pressure cold plasma
Hot vs Cold PlasmasHot vs Cold Plasmas
LowLow--Temperature (ldquoColdrdquo) PlasmasTemperature (ldquoColdrdquo) Plasmas[Non[Non--equilibrium Nonequilibrium Non--Thermal]Thermal][Non[Non equilibrium Nonequilibrium Non Thermal]Thermal]
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Plasma Lighting Technology
Thomas EdisonIncandescent Light Bulb
Fluorescent Lamps Compact fluorescent blub
Daniel McFarlan Moore
BirthplaceBirthplace ofof thethe FluorescentFluorescent LightLight BulbBulb EdisonEdison (Menlo(Menlo Park)Park) WestWest OrangeOrange NJNJ
Plasma Enhanced Technology
A small section of amemory chip
Straight holes like these canbe etched with plasmasmemory chip be etched with plasmas
BirthplaceBirthplace ofof solidsolid--statestate microelectronicsmicroelectronicsBellBell LaboratoriesLaboratories MurrayMurray HillHill NJNJ
Microchip fabrication with plasmas
The US Department of Energyrsquos Princeton Plasma Physics Laboratory (PPPL) is acollaborative national center for plasma and fusion science Its primary mission is tocollaborative national center for plasma and fusion science Its primary mission is todevelop the scientific understanding and the key innovations which will lead to anattractive fusion energy source Associated missions include conducting world-classresearch along the broad frontier of plasma science and technology and providing thehighest quality of scientific education
National Spherical Torus Experiment (NSTX)
Atmospheric Cold PlasmasErich Kunhardt amp Kurt Becker
An Atmospheric Pressure Plasma Generated with a
(Courtesy of K Becker)
Capillary-Plasma-Electrode Discharge
Two Types of plasmas
bull High‐temperature plasmas (Hot Plasmas)g p p ( )Tiasymp Te ge107 Keg fusion plasmas
T asymp T asymp T le 2 x 104 KTi asymp Te asymp Tg le 2 x 104 Keg arc plasma at normal pressure
bull Low‐temperature plasmas (Cold Plasmas)Ti asymp Tg asymp 300 KT ltlt T le 105 KTi ltlt Te le 105 Keg low‐pressure glow discharge
high‐pressure cold plasma
Hot vs Cold PlasmasHot vs Cold Plasmas
LowLow--Temperature (ldquoColdrdquo) PlasmasTemperature (ldquoColdrdquo) Plasmas[Non[Non--equilibrium Nonequilibrium Non--Thermal]Thermal][Non[Non equilibrium Nonequilibrium Non Thermal]Thermal]
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Plasma Enhanced Technology
A small section of amemory chip
Straight holes like these canbe etched with plasmasmemory chip be etched with plasmas
BirthplaceBirthplace ofof solidsolid--statestate microelectronicsmicroelectronicsBellBell LaboratoriesLaboratories MurrayMurray HillHill NJNJ
Microchip fabrication with plasmas
The US Department of Energyrsquos Princeton Plasma Physics Laboratory (PPPL) is acollaborative national center for plasma and fusion science Its primary mission is tocollaborative national center for plasma and fusion science Its primary mission is todevelop the scientific understanding and the key innovations which will lead to anattractive fusion energy source Associated missions include conducting world-classresearch along the broad frontier of plasma science and technology and providing thehighest quality of scientific education
National Spherical Torus Experiment (NSTX)
Atmospheric Cold PlasmasErich Kunhardt amp Kurt Becker
An Atmospheric Pressure Plasma Generated with a
(Courtesy of K Becker)
Capillary-Plasma-Electrode Discharge
Two Types of plasmas
bull High‐temperature plasmas (Hot Plasmas)g p p ( )Tiasymp Te ge107 Keg fusion plasmas
T asymp T asymp T le 2 x 104 KTi asymp Te asymp Tg le 2 x 104 Keg arc plasma at normal pressure
bull Low‐temperature plasmas (Cold Plasmas)Ti asymp Tg asymp 300 KT ltlt T le 105 KTi ltlt Te le 105 Keg low‐pressure glow discharge
high‐pressure cold plasma
Hot vs Cold PlasmasHot vs Cold Plasmas
LowLow--Temperature (ldquoColdrdquo) PlasmasTemperature (ldquoColdrdquo) Plasmas[Non[Non--equilibrium Nonequilibrium Non--Thermal]Thermal][Non[Non equilibrium Nonequilibrium Non Thermal]Thermal]
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
The US Department of Energyrsquos Princeton Plasma Physics Laboratory (PPPL) is acollaborative national center for plasma and fusion science Its primary mission is tocollaborative national center for plasma and fusion science Its primary mission is todevelop the scientific understanding and the key innovations which will lead to anattractive fusion energy source Associated missions include conducting world-classresearch along the broad frontier of plasma science and technology and providing thehighest quality of scientific education
National Spherical Torus Experiment (NSTX)
Atmospheric Cold PlasmasErich Kunhardt amp Kurt Becker
An Atmospheric Pressure Plasma Generated with a
(Courtesy of K Becker)
Capillary-Plasma-Electrode Discharge
Two Types of plasmas
bull High‐temperature plasmas (Hot Plasmas)g p p ( )Tiasymp Te ge107 Keg fusion plasmas
T asymp T asymp T le 2 x 104 KTi asymp Te asymp Tg le 2 x 104 Keg arc plasma at normal pressure
bull Low‐temperature plasmas (Cold Plasmas)Ti asymp Tg asymp 300 KT ltlt T le 105 KTi ltlt Te le 105 Keg low‐pressure glow discharge
high‐pressure cold plasma
Hot vs Cold PlasmasHot vs Cold Plasmas
LowLow--Temperature (ldquoColdrdquo) PlasmasTemperature (ldquoColdrdquo) Plasmas[Non[Non--equilibrium Nonequilibrium Non--Thermal]Thermal][Non[Non equilibrium Nonequilibrium Non Thermal]Thermal]
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Atmospheric Cold PlasmasErich Kunhardt amp Kurt Becker
An Atmospheric Pressure Plasma Generated with a
(Courtesy of K Becker)
Capillary-Plasma-Electrode Discharge
Two Types of plasmas
bull High‐temperature plasmas (Hot Plasmas)g p p ( )Tiasymp Te ge107 Keg fusion plasmas
T asymp T asymp T le 2 x 104 KTi asymp Te asymp Tg le 2 x 104 Keg arc plasma at normal pressure
bull Low‐temperature plasmas (Cold Plasmas)Ti asymp Tg asymp 300 KT ltlt T le 105 KTi ltlt Te le 105 Keg low‐pressure glow discharge
high‐pressure cold plasma
Hot vs Cold PlasmasHot vs Cold Plasmas
LowLow--Temperature (ldquoColdrdquo) PlasmasTemperature (ldquoColdrdquo) Plasmas[Non[Non--equilibrium Nonequilibrium Non--Thermal]Thermal][Non[Non equilibrium Nonequilibrium Non Thermal]Thermal]
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Two Types of plasmas
bull High‐temperature plasmas (Hot Plasmas)g p p ( )Tiasymp Te ge107 Keg fusion plasmas
T asymp T asymp T le 2 x 104 KTi asymp Te asymp Tg le 2 x 104 Keg arc plasma at normal pressure
bull Low‐temperature plasmas (Cold Plasmas)Ti asymp Tg asymp 300 KT ltlt T le 105 KTi ltlt Te le 105 Keg low‐pressure glow discharge
high‐pressure cold plasma
Hot vs Cold PlasmasHot vs Cold Plasmas
LowLow--Temperature (ldquoColdrdquo) PlasmasTemperature (ldquoColdrdquo) Plasmas[Non[Non--equilibrium Nonequilibrium Non--Thermal]Thermal][Non[Non equilibrium Nonequilibrium Non Thermal]Thermal]
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Hot vs Cold PlasmasHot vs Cold Plasmas
LowLow--Temperature (ldquoColdrdquo) PlasmasTemperature (ldquoColdrdquo) Plasmas[Non[Non--equilibrium Nonequilibrium Non--Thermal]Thermal][Non[Non equilibrium Nonequilibrium Non Thermal]Thermal]
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
LowLow--Temperature (ldquoColdrdquo) PlasmasTemperature (ldquoColdrdquo) Plasmas[Non[Non--equilibrium Nonequilibrium Non--Thermal]Thermal][Non[Non equilibrium Nonequilibrium Non Thermal]Thermal]
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
How do we make plasmasHow do we make plasmas
Supply Energyeg Heat transfer radiation electric powerhellip
For many plasma applicationsFor many plasma applications an Electric Field is applied to a gaseous environment
Plasma or Gaseous DischargePlasma or Gaseous Discharge
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
LowLow--Pressure Glow Discharge PlasmasPressure Glow Discharge Plasmas
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Plasmas are easier to be generated at low pressures
Low pressure plasmas (1 T f T )
at low pressures
are well understood
are used extensively nowadays
(1 mTorr ~ a few Torr)
are used extensively nowadays (eg in semiconductor industry for computer chips manufacturing)
However to generate low pressure plasmas
vacuum chambers + + = expensive vacuum pumps
pressure monitoring and pressure control devices
+ + =Generate Plasmas at Atmospheric PressureGenerate Plasmas at Atmospheric Pressure
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
What happens at air pressureWhat happens at air pressure
bull No vacuum is involvedDiffi l d ibull Difficult to generate and sustain
bull Run into some challenges such as glow toarc transition ndash Non controllable
Arc Discharge thermal plasma-Itrsquos hot and detrimental-Gas temperature can reach as high as 2x104 KGas temperature can reach as high as 2x10 K- Low voltage drop at cathode- High cathode current density
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
High Pressure Microplasmas
Stabilization of high-pressure plasmas ldquopd scalingrdquo ldquoprdquo uarr soplasmas pd scaling p uarr so ldquodrdquo darr to keep breakdown voltage low and minimize instabilities after breakdown -
MicroplasmasDimension a few millimeterDimension a few millimeter down to and below 100 m
Paschen Breakdown CurveH H i 60 100Human Hair 60 ndash 100 m
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
How do we solve this problemHow do we solve this problem
Transient (pulsed) plasmas In atmospheric plasmas for efficient gas heating atleast 100-1000 collisions are necessary Thus if the plasma duration is shorterleast 100 1000 collisions are necessary Thus if the plasma duration is shorterthan 10-6 ndash 10-5 s gas heating is limited Of course for practical purposes suchplasma has to be operated in a repetitive mode eg in trains of microsecondpulses with millisecond intervals
Micro-confinement Gas heating occurs in the plasma volume and the energy iscarried away by thermal diffusionconvection to the outside If the plasma has asmall volume and a relatively large surface gas heating is limited
Dielectric Barrier Discharges These plasmas are typically created betweenmetal plates which are covered by a thin layer of dielectric or highly resistivematerial The dielectric layer plays an important role in suppressing the currentthe cathodeanode layer is charged by incoming positive ionselectrons whichreduces the electric field and hinders charge transport towards the electrodeDBD also has a large surface-to-volume ratio which promotes diffusion lossesand maintains a low gas temperatureand maintains a low gas temperature
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Advantages of Microplasmas Advantages of Microplasmas
bull Low-cost of implementationpbull System flexibilitybull Atmospheric pressure operationbull High densities and high reaction ratesbull High densities and high reaction ratesbull Fast and efficient processesbull Easy to generate and sustain for a variety of gas mixtures
Gl lik d diffbull Glow-like and diffusebull Non-equilibrium (Te gt Tg) to thermalbull Unique chemistryq y
hellip a new realm of plasma sciencehellip a new realm of plasma science
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
What can we do with microplasmasWhat can we do with microplasmas
Material Synthesis Plasma display Surface Treatment Lighting
OzoneOzone generation for water cleaning
Bio-applicationMaterial processing Dental application
and Many morehellip
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Some High Pressure microplasma reactors Some High Pressure microplasma reactors
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)
Hi h V l
HighVoltage
High VoltageElectrode
ACGenerator
DielectricBarrier
Generator
G
Microplasmas
GroundElectrode
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Faradayrsquos Dielectric CapacitorsFaradayrsquos Dielectric Capacitors
Faradays Dielectric Capacitor (circa 1837)
Michael Faraday (1781 ndash 1867) Capacitance INCREASED
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Historical Ozone Tube of W Siemens (1857)Historical Ozone Tube of W Siemens (1857)
Werner v SiemensP d frsquo A l d Ch i d Ph ik 102 66 (1857)Poggendorfrsquos Annalen der Chemie und Physik 102 66 (1857)
ldquoOzone Production in an Atmospheric-PressureDielectric Barrier Dischargerdquo
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Dielectric Barrier Discharge
Dielectric Barrier DischargeDielectric - Barrier Discharge ConfigurationsHigh
VoltageAC
Generator
High VoltageElectrode
DielectricBarrier
DielectricBarrier
High VoltageElectrode
Discharge
DischargeGeneratorGround
Electrode
Electrode
GroundElectrode
Discharge
H E Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications toHE Wagner R Brandenburg et al The barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 p417-436 (2003)
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Typical operational conditions of barrier discharges Typical operational conditions of barrier discharges
Electric field strength E of first breakdown asymp150 Td (p = 1bar T=300 K)
Voltage Vpp 3ndash20 kV
Repetition frequency f 50 Hzndash30 kHz
Pressure p 1ndash3 bar
Gap distance g 02ndash5mm
Dielectric material thickness d 05ndash2mm
Relative dielectric permittivity r 5ndash10 (glass)
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Single and double DBD
Single dielectric Double dielectric
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Role of the Dielectric (Insulator)
Th di l t i i th k f thThe dielectric is the key for the properfunctioning of the discharge
Serves two functions
1 Limits the amount of charge transportedby a single microplasma
2 Distributes the microplasmas over theentire electrode surface area
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Equivalent Circuit of a Microdischarge
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Microdischarge Activity and U-Q Lissajous Figure
B Eliasson and U Kogelschatz IEEE Transactions Plasma Science Vol 19 Issue 6 1063-1077 (1991)
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Fundamental Operation of the Dielectric Barrier DischargeFundamental Operation of the Dielectric Barrier Discharge
bull Many of relevant plasma processes that areof importance to achieving our goal occuron time scales that allow us to study themon time scales that allow us to study them
bull Optical emission spectroscopic studies willallow us to determine the temporal andspatial development of important plasmaspatial development of important plasmaspecies such as radicals (OH NO variousoxygen radicals) with high time resolution(less than 10 ns) and a spatial resolution onthe scale of mm in the plasma volumepfollowing pulsed plasma excitation
Time scale of the relevant processes of the DBD
HE Wagner R Brandenburg et al lsquoThe barrier discharge basic properties and applications tosurface treatmentrsquo Vacuum 71 417-436 (2003)
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Fundamental Operation of the DBDFundamental Operation of the DBD
Electron DensityTemporal Development (ns)
y
Outer Contour Linen = 1010 cm-3ne = 1010 cm 3
Inner Contour Linene = 1014 cm-3
Streamer Propagation in 1 bar AirAA Kulikovsky IEEE Trans Plasma Sci 25 439-446 (1997)
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Starting Phase of a Microdischarge (1 bar 20 CO2 80 H2)
E0=34 kVcm1010 cm-3
1010 cm-3 ne=1012 cm-3
1mm10 cm
ne=108 cm-3
An electron avalanche propagates towards the anode
Reverse propagationtowards the cathodepropagates towards the anode towards the cathode
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Cathode Layer Formation
E0=34 kVcm1010 cm-39 3 0
1mm
1010 cm-3
10 cmne=109 cm-31014
10131014
1013
10 cm1012
Just before the peak of the total current
Peak currentof the total current
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Numerical Results of Microdischarge Formationin Dielectric Barrier Discharges
Local Field Collapse in Area Defined by Surface Discharge
ne=109cm-3 ne=1014 cm-3
Gap
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
C C-- - --- - - CG
CD
-- - - CG
CD
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Principals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD MicroplasmasPrincipals of DBD Microplasmas
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Dielectric Barrier Discharge (DBD)Dielectric Barrier Discharge (DBD)Electric Field
B kdBreakdown
Electrons amp Ions Discharge Physics
Excited SpeciesPlasma Chemistry
Chemical Reactions
OzoneGeneration
SurfaceTreatment
PollutionControl
ExcimerFormation CO2 Lasers Hydrogenation
of CO2
Excimer Lamps Plasma Displays
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
How A Plasma Display Works
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
How A Plasma Display Work
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Plasma Display TelevisionsPlasma Display Televisions
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Ozone Generator
3 O 2 O
Dielectric Barrier Discharge
3 O2 2 O3
OO22 OO33++OO22Ondash ndashO3O2
O2O2
Ondash ndash
endash O2Ondash ndash O2endash
O3
O3O2O2 O2
HeatHeatHeatHeat
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Properties of Ozone (O3)
T i t i f f Tri-atomic form of oxygen
Most powerful commercial oxidizing agent
Unstable - must be generated and used onsite
Limited solubility in water but more so than oxygenLimited solubility in water but more so than oxygen
Leaves a dissolved residual which ultimately converts back to oxygenconverts back to oxygen
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Discharge Tubes in Ozone GeneratorsDischarge Tubes in Ozone Generators
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Traditional
Ozone Generator
with Glass Tubes
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Generation of OzoneGeneration of Ozone
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Generation of OzoneAdvantages of Enamel Dielectrics
Proven Patented Designbull Simplicity
Si l Di l i Cbull Single Dielectric Componentndash Reduced number of Dielectrics
bull Safety ndash Lower operating voltage
(lt 4000 V)bull Reliabilty
ndash Fused Dielectrics ensure continuous production
bull Lowest Power Consumption Operational Savingsndash Operational Savings
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Modern Ozone GeneratorModern Ozone Generator
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Ozonia Advanced Technology Ozone GeneratorOzone Generator
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Generation of OzoneGeneration of Ozone
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Generation of Ozone
Power Supply UnitPower Supply Unit
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
IGBT Inverter CircuitMain Circuit Breaker
HV 480 Volts60 Hz3 Phase Supply
C I
450KVAPow er to
GeneratorFILTER
CONVERTER INVERTERTRANSFORMER
C I450KVA Power Stage
CONTACTOR
bull Latest in Power Semiconductor Technology Modular Design
bull Utilizes IGBTrsquos (Insulated Gate Bi‐Polar Transistors) Converter and Inverter Components
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Ozone Water Treatment
B bbl Diff iB bbl Diff iBubble DiffusionBubble Diffusion
Easy to use
Low energy usage Low energy usage
Mass transfer efficiencies to gt 90
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Ozone Process Flow DiagramOzone Process Flow DiagramVent to
Atmosphere
O OOxygen
Off-Gas Blower
Ozone Destruct Unit
10 12
O3O2
LOX
10-12 O3
Ozone Generators
Ozone Contact ChamberLOX T k Generators Chamber
VaporizersLOX Tank
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Municipal Ozone Installations
Ozonia Installations Ozone Plant Size [lbday] Start-Up DateKey Ozonia Installations (Partial List)
Los Angeles CA 10000 1986Fairfax VA ndash Corbalis 9000 2003MWD CA ndash Mills 9 000 2003
Ozonia Installations Ozone Plant Size [lbday] Start Up Date
MWD CA Mills 9000 2003Fairfax Co VA ndash Griffith 9000 2004MWD CA ndash Jensen 18750 2005Indianapolis IN ndash Belmont AWT 12000 2007I di li IN 12 000 2007Indianapolis IN ndash Southport AWT 12000 2007MWD CA ndash Diemer 13400 2008MWD CA ndash Weymouth 13400 2009
Ozonia North America - Potable Water SummaryTotal Number of Installations 90Total Installed Production gt 265000 lbsdayTotal Installed Production 265000 lbsday
Revision -B
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Ozone Water TreatmentOzone Water Treatment
MWD Mills WTP - California
3 3 000 lbsda of o one3 3 000 lbsda of o one3 x 3000 lbsday of ozone3 x 3000 lbsday of ozone
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Ozone Water TreatmentOzone Water TreatmentOzone Ozone -- How it worksHow it works
OxidantOxidant DisinfectantDisinfectant
bullbull Breaks double carbon Breaks double carbon bondsbonds
bullbull Kills by cell lysing or Kills by cell lysing or causing the cell wall tocausing the cell wall tobondsbonds
bullbull Creates OHCreates OHbullbull radicals radicals which break higher carbon which break higher carbon
causing the cell wall to causing the cell wall to rupture rupture
bullbull AttacksAttacks allall bacteriabacteriabondsbondsbullbull Increased temp and pH Increased temp and pH
accelerates Oaccelerates O33
Attacks Attacks allall bacteria bacteria virus cysts and spores virus cysts and spores in varying degreesin varying degreesaccelerates Oaccelerates O33
decomposition to OHdecomposition to OHbullbull
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Micro-organism DNA
Capsule AdenineAdenine
Cell wall ThymineThymine
CytosineCytosine
GuanineGuanine
NuclearmaterialCellmembrane
material
Typical Bacterium DNA
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Microbial Growth at Various Ozone ConcentrationsConcentrations
Growth likely
Growth possibleGrowth possible
NO GROWTH
0004 0008 0012 0016 0020
Ozone concentration (mgl)Ozone concentration (mgl)
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Typical Water Treatment UsageTypical Water Treatment Usage
Application O3 mgl Contact timeUltra Pure Water 005 - 025 sec ndash min
Water bottling 04 ndash 10 5 ndash 10 min
Swimming pools ampspas
01 ndash 075 4 minutes
Potable taste amp odor 15 ndash 50 5 ndash 10 mindisinfection
Microfloculation 10 ndash 30 5 ndash 10 min
Lignin amp tammin 3 0 10 0 10 30 minLignin amp tamminremoval
30 ndash 100 10 ndash 30 min
Municipal wastewater 50 ndash 150+ 15 ndash 30 min
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Ozone Water TreatmentOzone Water TreatmentOzone Ozone ndashndash Municipal ApplicationsMunicipal Applications
bullbull Taste and OdorTaste and Odor
bullbull Color RemovalColor Removal
bullbull Disinfection Without Trihalomethanes (THMs)Disinfection Without Trihalomethanes (THMs)
bullbull Improved Filtration Efficiency and FlocculationImproved Filtration Efficiency and Flocculation
bullbull Cryptosporidium DeactivationCryptosporidium Deactivation
bullbull Giardia amp Virus InactivationGiardia amp Virus Inactivation
bullbull Oxidation Oxidation -- Organics Fe amp MnOrganics Fe amp Mn
bullbull Wastewater disinfectionWastewater disinfection
bullbull BOD COD and TOC reductionBOD COD and TOC reduction
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Applications of Ozone
Wastewater Treatmentbull Disinfection of Secondary and Tertiary Effluentsbull Color Reductionbull Color Reductionbull TOC Oxidation (Industrial)bull Oxidation of Odor Causing Compoundsbull Oxidation of Endocrine Disruptors (EDCrsquos) and p ( )
Pharmaceutically Active Compounds (PACrsquos)
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Applications of Ozone
What are Endocrine Disruptors (EDCrsquos) and What are Endocrine Disruptors (EDCrsquos) and Ph ti ll A ti C d (PACrsquo )Ph ti ll A ti C d (PACrsquo )Pharmaceutically Active Compounds (PACrsquos)Pharmaceutically Active Compounds (PACrsquos)
bullbull EDCrsquosEDCrsquos andand PACrsquosPACrsquos areare NaturallyNaturally andand SyntheticSyntheticdd th tth t ff tff t thth b lb l llcompoundscompounds thatthat maymay affectaffect thethe balancebalance oror normalnormal
functionsfunctions inin animalsanimals andand humanshumans
What can EDCrsquos and PACrsquos doWhat can EDCrsquos and PACrsquos do
bullbull Even in very small concentrations these compounds Even in very small concentrations these compounds y py pcan can disruptdisrupt normal bodily functionsnormal bodily functions
bullbull ManMan--made chemicals can trick the bodies endocrine made chemicals can trick the bodies endocrine system system
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Applications of Ozone
Examples of Endocrine Disruptors1000rsquos of compounds that may be Investigated as EDCs ndash Some examples are
bullbull Synthetic HormonesSynthetic Hormonesbullbull Naturally Occurring Estrogens Naturally Occurring Estrogens
Health and Beauty AidsHealth and Beauty Aidsbullbull Health and Beauty AidsHealth and Beauty Aidsbullbull SolventsSolventsbullbull PesticidesPesticidesbullbull SurfactantsSurfactantsbullbull PlasticsPlastics
F i idF i idbullbull FungicidesFungicides
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Ozone Water TreatmentOzone Water Treatment
Ozone Ozone -- Industrial ApplicationsIndustrial Applications-- Ultrapure Water for Pharmaceutical ApplicationsUltrapure Water for Pharmaceutical Applications
-- Wastewater disinfection color removalWastewater disinfection color removal
-- Soil and Groundwater Remediation Soil and Groundwater Remediation
-- Cooling Tower Water TreatmentCooling Tower Water Treatment
-- Food ProcessingFood Processing
-- Aquaculture AquariumsAquaculture AquariumsAquaculture AquariumsAquaculture Aquariums
-- Beverage ApplicationsBeverage Applications
P l amp P Bl hiP l amp P Bl hi-- Pulp amp Paper BleachingPulp amp Paper Bleaching
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
High Purity OzonationHigh Purity Ozonation
Microchip manufacturingMicrochip manufacturing
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
What are the current issues in large-scale gozone generationg
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Experimental Setup
Front view of the two units after the redesign and reworking ofthe gas water and instruments connectionsthe gas water and instruments connections
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Experimental Setup
Top view of the twoexperimental unitsexperimental unitsSpectroscope (notshown) is to the left ofthe DBD The units weredifferent with respect todifferent with respect totheir electrodes onehad only the electrodecoated with thedielectric (ldquosingle-dielectric ( single-coatedrdquo) the other onehad the electrode andthe anode coated withthe dielectric (ldquodouble-the dielectric ( double-coatedrdquo)
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Basics Generation of OzoneBasics Generation of Ozone
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
SpectroscopyPlasma
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Plasma Absorption SpectroscopyPlasma Absorption Spectroscopy
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra in pure oxygen (black curve) and at approximately 10wt N2 admixture (red line) N2O5 peaks appear at124 1 d 1 2 11245 cm-1 and at 1725 cm-1
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Infrared Absorption SpectroscopyInfrared Absorption Spectroscopy
IR spectra of several methane variations The green curve envelopes all of the methane peaks at 1325 cm-1recorded at smaller methane admixtures Simultaneously the N2O5 peaks disappear as the methane peaks appear
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
N2O5 FormationN2O5 Formation2 52 5p=2 bara cwt=20degC q=35kWm2 f=1450Hz
45N2O5 AT95
30
35
40
N
2 B
lend
ing
N2O AT95N2O5 IGSN2O IGSN2O5 LGN2O LG
1 5
20
25
nt [p
pmV]
3
wt
05
10
15
NO
x co
nten
005 7 9 11 13 15 17
ozone conc [wt]
Amount of formed N2O5 and N2O as a function of ozone concentration at 3 wt of nitrogen admixture and fori l dvarious electrode arrangements
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Plasma Emission SpectroscopyPlasma Emission Spectroscopyp pyp py
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Relative Emissions of the Ozonizer plasmaRelative Emissions of the Ozonizer plasma
Region 300- 850 nm from individual (calibrated) regions (smoothed by PeakFit) Single-coated ozone generator Inlet side
3 5E+06
30E+06
35E+06
7 9
20E+06
25E+06
nten
sity
au
2
311 12
10E+06
15E+06
In 4
5
6 8 10
14
15
16
17
00E+00
50E+05
280 300 320 340 360 380 400 420 440 460 480 500 520 540 560 580 600 620 640 660 680 700 720 740 760 780 800 820 840 860
Wavelength nm
1 13
Wavelength nm
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Absolute Emission of the DBD PlasmaAbsolute Emission of the DBD Plasma
Intensities in (O2+3 wtN2) plasma
1 20E+04
100E+04
120E+04
600E+03
800E+03
nten
sity
(au
)
200E+03
400E+03
In
O(777)
000E+00200 250 300 350 400 450 500 550 600 650 700 750 800 850
Wavelength nm
Intensities in 3 wtN2+O2 plasmaIntensities in 3 wtN2+O2 plasma
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Plasma Chemistry in OzonizersPlasma Chemistry in Ozonizers
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
N
3
NO2
O2 O3
NO
N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
Primary electron-driven chemical reactions leading to the formation of N2O5 and N2O in a dry air plasma
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Plasma emission diagnostics role of N2Plasma emission diagnostics role of N2
Dry Air O2 N2
e - e -
O N2 N O2
O3 NO
O2 N O2
O3
O
N
ON
NO2
O2O3
N
NO N
NO2 O3
N2O
NO3 N
N2O4
NO2
NO2
N2O5
NO3
ONbullWith N2 present ndash less oxygen atoms are formed However the difference in intensity is
very small
Modeling of plasma chemistry incl the NxOy chemistry up to N2O5 for different Oxygen Nitrogen mixtures varying power deposition scenarios
and initial ozone background concentrations (up to 15) previously done
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
The role of N2 must be related to its by-products reacting on the surface of the electrodeThe role of N2 must be related to its by-products reacting on the surface of the electrode
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f O
The following facts which were verified on various oxygen-fed ozone generator vessels (utilizedwith and without pickling and passivation) were established
Ab 8 t f OAbove 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)
Above 8 wt of O3
1 Deterioration of the generator performance without N2 admixture even with pampp(removal of the pampp oxide layer during aggressive cleaning of surfaces is equivalent to thecase itho t pampp)case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of the
case without pampp)
2 The experiments performed by Pontiga et al in 2004 confirm the above conclusion The by-products seem to just conserve the properties of a surface it will deteriorate withoutthem A deterioration of the surface is due to oxidation which extends the thickness of thethem A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
them A deterioration of the surface is due to oxidation which extends the thickness of theoxide layer N2O5 is found to deposit as crystalline substance on surfaces which are slightlycooler than the N2O5-carrying gas An N2O5 layer seems to inhibit the advanced oxidation ofthe stainless steel surface
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
The Role of nitrogen (N2) in ozone generationThe Role of nitrogen (N2) in ozone generation
Three possibilities have to be considered for the oxygen-fedozone generator
Three possibilities have to be considered for the oxygen-fedozone generatorozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in
ozone generator
bull Excited N2 molecules lead to an increased O2 dissociation in2 2such case an increased efficiency is correlated to the N2admixture
2 2such case an increased efficiency is correlated to the N2admixture
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The by-products perform a chemicalphysical process on theelectrodes which turns out to be beneficial
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2
bull The UV emission from O2 dissociation that leads to photon orlight splitting of O3 is suppressed by N2g p g 3 pp y 2g p g 3 pp y 2
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Effect of methane on ozone efficiency and specific powerEffect of methane on ozone efficiency and specific power
Effect of Methane on Ozone Content in Outlet Gas and on Specific Power Pure O2
13 12
10
11
12
t 8
10
8
9
10
ne c
onte
nt w
t
6
8
ecifi
c po
wer
kW
hlb
5
6
7
Ozo
n
2
4 Spe
400E+00 20E+03 40E+03 60E+03 80E+03 10E+04 12E+04
Methane in feedgas ppm
0
Ozone content in the outlet gas Specif ic pow er of the ozone generatorg p p g
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Effects of N2 and CH4Effects of N2 and CH4
Pi t f h t lli N O t tPicture of an amorphous-crystalline N2O5 structurecaptured at the Orlando Skylake water plant in 2006
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Plasma Chemistry with CH4 Impurities
OxygenO2 N2
e - e -
CHO N2
NO2
O NO
O2 N O2 O3
NOH
CH4e-
O3 NO
NO2
O2O3NO N
NO2 O
NO2
NO2
N2ONO3
N
O3
NO2
NO
HNO3
N2O4
N2O5
NO2
NO3
N2O5
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Effect of methane on the electrode surfaces
a) b)
Inlet Outlet Outlet
) d)
I l t I l t
c) d)
Electrode of the ozone generator afterseveral hours in CH8O2 and up to 2 wt of methane (a b c)
Inlet Inlet
three hours in CH8O2+traces of N2 and up to 1 wt of methane (d) Visible change of discharge character at about 13 length of electrode (a d)
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Kinetics of CHx Conversion without N2
conversion by collisions
O2 + CHx 12wt O3 + CO2 +H2O
deposition vaporizationby sputtering
ibl b l 1000 CHreversible process below 1000ppm CH4
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Effect of water on electrode surface with N2
Inlet
OutletOutlet
Electrode of the ozone generator after several hours in H OO N
Inlet
Electrode of the ozone generator after several hours in H2OO2N2
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Effect of water on electrode surface
Long term effect (800 hrs) of H2OO2N2
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Kinetics of CHx Conversion with N2
conversion by collisionsHNO3 formation
O2 + N2 +CHx 12wtO2 + CO2 +H2O + HNO3
deposition vaporizationby sputtering
H2O + HNO3
by sputtering
irreversible process above a N2 threshold () ltlt 1000ppm N2
sticky deposit
p 2 ( ) pp 2 any CH4 concentration (60ppm)
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Plasma Chemistry with CH4 ImpuritiesPlasma Chemistry with CH4 Impurities4
bull Formation of NO and NO2 depends on O3 N2 and gas temperature Conclusion N2 admixture is the key factor
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
SummarySummaryyyThe mechanisms of formed NOx by-products follows the sameThe mechanisms of formed NOx by-products follows the sameprinciples as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentration
principles as the air fed ozone generators the amount of formed N2O5is found to depend on just three parametersozoneozone concentrationconcentrationozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)
ozoneozone concentrationconcentrationnitrogen admixturecooling water temperature ( = gas temperature)g p ( g p )
The conversion of methane to OH and H2O is found to depend on
g p ( g p )
The conversion of methane to OH and H2O is found to depend ondissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)
dissociation by electron impact ( microdischarge)energy distribution of electrons in the microdischarges (discharge gap)discharge gap)discharge gap)
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
How do you optimize an ozone generatorg
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Scientific ApproachScientific ApproachTheoretical Experimental
pppp
c [wt]
f [Hz]
c [wt]
f [Hz]
[kW]UUUβ1
1Cf4αPn
1iiminpeakimin
iiD
q [kWm2]q [kWm2]
150
180
][V]voltagepeakUpeak
[]cylinder perslicesofamountnsliceii
whereth
09 00
30
60
90
120
effic
ienc
y [
][0tdj t bl[F]sliceisdielectricofecapacitancC
[Hz]frequencyf[V]sliceivoltageminimumiUmin
thiD
th
10
28
46
64
82
39
107
176
244 power density
[kWm2]
ozone conc [wt][]CCβ
][0parameteradjustableα
iDiGi
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Impact of Power Inductionp
350
400
wer
200
250
300
App
lied
Pow
Arr C 2Arr D +0
Arr E +45Arr F +7
Arr G +3
5 0
100
150
Frac
tion
of
1 2 3 4
ReferenceArr B unstable
Arr C -2
00
50
4Position (1inlet 4outlet)
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Experimental Test Rigp g
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Experimental Test Rigp g
Outer grounded electrode (left picture) and the dielectric covered inner electrodes (right) d e ect c cove ed e e ect odes ( g t)
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Reference (Traditional) Arrangement
Inlet OutletGas flow direction
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Optimized Arrangement
Inlet OutletGas flow direction
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Intelligent Gap System (IGS)g p y ( )
Molecular Oxygen (O2) Ozone (O3)
O2 O3
yg ( 2) ( 3)
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Particle Size SynthesisParticle Size SynthesisByBy--Products Cluster FormationProducts Cluster Formationyy
high diffusion and deposition to surfaces
low diffusion rate good transport
high sedimentation on the structurehigh sedimentation on the structure
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Degreacutemont Technologies ndash OzoniaIntelligent Gap SystemIntelligent Gap System
G Vezzuacute JL Lopez A Freilich and K Becker Optimizationof Large-Scale Ozone Generators IEEE Transactions onPlasma Science Vol 37 No 6 p 890-896 (2009)
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
ConclusionsConclusionsConclusionsConclusionsFundamentals of ozone synthesis in a DBD plasmay p
ndash Highly filamented DBD discharges are best-suitedfor the production of ozone concentrations in therange of 6 to 14 wtrange of 6 to 14 wt
ndash The preferred characteristic of the microdischargesare Townsend-like at reduced electric fields Enaround 190 Townsend
ndash Detrimental side-effects induced by by-productscan be avoided by a proper design of the electrodecan be avoided by a proper design of the electrodearrangement The phenomenon is related to thediffusion rates of formed by-product clusters
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
ConclusionsConclusionsConclusionsConclusionsBenefits from DBD microplasma tailoring
ndash Reduced power consumption of up to 10 improvement
ndash Increased ozone concentrations of up to 14 now achievable
ndash Improved neutralization and conditioning of detrimental by-products
ndash Reduced system capital and operational cost
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
New technologies to improve ozone p
generatorg
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
HV Pulsed Power SwitchingHV Pulsed Power Switching
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Microchannel Generation of Ozone
Channel ArrayChannel Array
Microchannel
330 microm 230 microm
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Some Cap-DBD Devices Operating in Air
Increase of 60 of
Spacing 225 μmof 60 of plasma
No space
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Cap‐DBD ozone generation
bull Ozone concentration is evaluated via Eco S d l UV 100 O A l (0 01Sensors model UV-100 Ozone Analyzer (001 ndash 900 ppm wiht an accuracy of plusmn2)
bull Three reactors 6 tubings 6rdquo with spacings of 0 μm 225 μm and 500 μm running at 3 kV μ μ μ g
SpacingOzone Concentration
3 kV rms 4 kV rms3 kV rms 4 kV rms
0 μm 660 ppm
225 μm 550 ppm
For a device of such small scale these ozone levels are promising
500 μm 380 ppm
J Mahoney W Zhu VS Johnson KH Becker and JL Lopez Electrical and optical emissionmeasurements of a capillary dielectric barrier discharge European Physics Journal D Vol 60 441-447(2010)
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
QuestionsQuestions
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics
Thank YouFor more informationProf Jose L Lopez PhD
Thank YouFor more informationDepartment of Physics
Telephone (973) 761-9057Email joselopez1shuedu
Website wwwshueduacademicsartsciphysicsWebsite wwwshueduacademicsartsciphysics